Project Notre Dame arose as the spontaneous response of a group of BIM (Building Information Modeling) enthusiasts with a fascination for old buildings. Digital tools extend our ability to think about the world: where we’ve come from and where we’re going. Why should we restrict the use of BIM to the narrow confines of our day jobs? Crowd-sourced "learning by doing" has the potential to combine Wikipedia and Google Earth 3D to create a new kind of online museum experience. This case study describes the work of a global team of volunteers taking a deep dive into an 800-year-old building laden with cultural meaning, each one pursuing their interests and passions. How did they communicate? What did they discover? Come to the session and find out.